Professor Zerina Kapetanovic and researchers Jasmin Falconer and Geneva Ecola recently published their paper in IEEE Journal of Microwaves. Zerina is the lead researcher of the Stanford Smart Sensing Systems (S4) Lab

The key idea is that a resistor connected to an antenna can act as a completely passive and wireless temperature sensor. Our work demonstrates that thermal noise, caused by the random motion of electrons in the resistor, can be wirelessly scanned by a radiometer to measure its temperature, thus requiring no power at the sensor node. Unlike devices such as infrared cameras, this method allows for temperatures to be measured that are out of view of the scanner, such as underground or behind barriers. The sensor is passive, thus requiring no maintenance and allowing for operation under harsh conditions.

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• IEEE Journal of Microwaves > Volume: 5 Issue: 4, 'Wireless Johnson Noise Thermometry for Passive Temperature Sensing'